E-cigarette advertising may be leading children to believe occasional tobacco smoking is not harmful, and is potentially prompting more young people to experiment with smoking, a study has claimed.

Researchers from the University of Cambridge and the University of North Carolina recruited more than 400 English children for the study.

The children were aged 11 to 16, had never smoked or vaped before and were randomly allocated to one of three groups.

One group was shown 10 adverts that depicted e-cigarettes as glamorous, a second group saw 10 adverts that portrayed them as healthy, and a third control group was shown no adverts.

The children were then asked questions to check their attitudes towards smoking and vaping.

Children shown the adverts were no more or less likely than the control group to see tobacco smoking as appealing and all three groups understood that smoking more than 10 cigarettes a day was harmful.

But both groups exposed to the e-cigarette adverts, both healthy and glamorous, were less likely to believe that smoking one or two tobacco cigarettes occasionally was harmful.

There is concern that the increasing exposure of children to e-cigarette adverts could be contributing to high rates of experimentation.

Dr Milica Vasiljevic, from the Department of Public Health and Primary Care at the University of Cambridge, said: "This is worrying, as we know that even occasional tobacco smoking is bad for your health."